Weather in United Kingdom in January

January climate overview

Daytime highs across United Kingdom in January run from 7.4°C (London) to 9.1°C (Cornwall). Days over 25°C are rare anywhere in United Kingdom in January. Nights average 3.7°C; the coldest 10% of nights in London fall to -2°C or below.

Rainfall in January

Expect around 14 rainy days (1 mm or more) in January, with London the driest (12 days) and Cornwall the wettest (16 days). The wettest January at Cornwall between 1991 and 2020 was 2018 with 149 mm; the driest was 1997 with 15 mm.

Sea temperature

The sea averages 9.8°C around United Kingdom in January. That is cold for swimming without a wetsuit.

Sunshine and daylight

Around 2.2 hours of sunshine a day on average, out of 8.3 hours of daylight (sunshine estimated from cloud cover).

January against the rest of the year in United Kingdom

January is the 12th warmest month of the twelve in United Kingdom. It is 0.4°C cooler than December and 0.2°C warmer in February. The hottest month here is July (20°C) and the coolest January (8°C).

Which part of United Kingdom in January?

• Most sunshine: Cornwall, 2.2 h a day.
• Driest: London, about 12 rainy days.
• Warmest sea: Cornwall, 10°C.
• Hottest: Cornwall, 9°C by day.
• Coolest (better for walking and cities): London, 7°C.

What to pack for United Kingdom in January

Based on the averages: proper layers and a jacket - daytime highs average only 8°C; a warm layer for evenings, when it drops to around 4°C; a rain jacket - roughly 14 wet days.

Similar weather elsewhere in January

Within 1.5°C of United Kingdom's January daytime average: Madrid (10°C), Florence (9°C), Pula (9°C, sea 11°C), Thassos (9°C, sea 13°C), Istanbul (8°C, sea 8°C). See the full ranking for January.

Cornwall for milder weather, London for fewer rainy days

Cornwall is the warmer option here, reaching 9°C by day and dropping to 5°C at night. That makes it a better fit if you dislike the cold, but its 16 rainy days mean waterproof clothing should take priority over fair-weather plans. London is cooler at 7°C during the day, with nights falling to 2°C, so evenings call for warmer layers. Its 12 rainy days give it the advantage on rain frequency, not warmth. The choice is a trade-off: Cornwall suits travellers who value milder temperatures, while London suits those willing to accept colder conditions in return for fewer days with rain.

Plan around the weather rather than a fixed outdoor schedule

Pack a warm coat, layers and waterproof footwear, and keep outdoor plans easy to rearrange. The daytime averages are cold enough that sitting outside may feel less appealing than walking, while the lower night temperatures make an extra layer useful after dark. Sunshine averages just 2.2 hours, so do not build the trip around clear skies. Use brighter spells for time outdoors and leave room for indoor breaks when rain arrives. January suits travellers comfortable with a weather-led holiday; it is a poor match if your main aim is to spend long stretches outside without thinking about clothing or shelter.